Republican presidential nominee Ronald Reagan said last night that the United States should agree to virtually all the new demands of Iran's Ayatollah Ruhollah Khomeini in return for the prompt release of the American hostages.

In a prepared statement he read before he and President Carter delivered separate speeches to the National Italian-American Foundation dinner, Reagan said the United States "can and should" agree to release Iranian assets in this country, cancel all claims against Iran and pledge nonintervention in Iran's domestic affairs.

These were three of the four conditions Khomeini set for the return of the hostages in a statement issued Friday in Tehran.

Reagan said Khomeini's fourth condition -- the return to Iran of the property of the late shah Mohammad Reza Pahlavi -- cannot be met without "due process of law."

"Having agreed to these points we must above all insist that the hostages be released immediately upon conclusion of an agreement, that there be no delays, introduction of additional demands or waiting for fulfillment of an agreement," he said.

The GOP nominee also pledged not to make negotiations over Iran's new conditions" and said that if elected "I will observe the terms of the agreement."

"Let me add that there should be no delay in freeing the hostages with any thought by Iran that it might get better terms after the election in November," Reagan said.

The statement was Reagan's most extensive of the campaign on the hostages and was clearly meant to put the president on the defensive on that explosive issue. Carter initially reacted cautiously to Knomeini statement, saying only that it would be studied, and he made no reference to Reagan's comments in his speech last night.

The United States has already pledged not to intervene in Iran's domestic affairs and neither the frozen Iranian assets nor the pending claims against Iran are likely to be major stumbling blocks in any negotiations for release of the hostages.

But by his statement last night, Reagan seized the initiative, staking out a position that may turn out to be essentially what the administration offers Khomeini in response to the new conditions.

Reagan refused to answer questions about his hostage statement, which was issued as he and the president maneuvered around each other at the Washington Hilton Hotel, coming within an hour of staging a sort of mini-debate before the dinner.

Earlier in the day, Carter invoked his prerogative to change his schedule and move ahead of his Republican rival on the program.

But Reagan countered by delaying his arrival at the Washington Hilton Hotel so he would not be sitting at the head table while Carter spoke.

White House press secretary Jody Powell said the last minute schedule change was made only because Carter wished to attend a fund-raising concert and reception late last night at Merriweather Post Pavilion in Columbia.

The texts of the two speeches for the dinner were similar in many respects as the two presidential candidates praised the courage of Italian immigrants, the contributions of Italian art and music to world culture and what both described as the Italian heritage of respect for family, hard work and patriotism.

Both candidates were received politely and applauded several times during their speeches, but neither appeared to generate a great deal of excitement in the audience.

Both speeches contained elements of the two candidates' basic stump appeals and they were most sharply at odds on the question of unemployment.

During his administration "we created 8 million jobs," the president said, while acknowledging "there are still too many unemployed."

Reagan said the test in the election for Italian Americans and others "is not simply who praises their values but who has the philosophy of government to put those values into effective action."

"On Labor Day, I was in Jersey City," the GOP nominee said. "The unemployment rate is almost 12 percent there. In Youngstown, Ohio, it is almost 14 percent, 25 percent in Flint, Mich. In those cities and many others all across America, the values we share are not being given the opportunity or the power to enhance our lives."

Reagan also reminded the largely Catholic audience of the Republican platform's support for tuition tax credits for parents who send children to parochial or private schools. Carter, who has increased federal funding of public education but who is opposed to tuition tax credits legislation, said his administration had made "the greatest contributions to education in history."

The president invoked has main campaign theme, that the 1980 election represents "a clear and crucial choice [between] two futures" for the country as he defended his record in office.

Replying indirectly to Reagan's charge that the administration has allowed U.S. military power to erode, Carter said, "We have kept our nation strong and therefore we have had four years of peace."

Among those in the audience was Anthony Casamento, an Italian-American World War II veteran who was belatedly awarded the Medal of Honor by the president Friday at a White House ceremony.

Carter referred to Casamento as he praised the "precious set of values" bequeathed to the country by Italian immigrants.

"They taught us a selfless, unshakable respect for family," he said. They taught us a proud, bold patriotism as they offered even their lives or their new country . . . The immigrants taught us a reverence for the dignity of work."

Reagan used a similar theme as he spoke of the "community of values" shared of the "community of values" shared by Americans of different ethnic backgrounds.

"It transcends party lines," he said. "It transcends ethnic and religious and regional lines. It has at its center a belief in the values of family, work, neighborhood, peace and freedom -- those values that are at the heart of the Italian and the American tradition. There are Republicans and Democrats and independents who share those values and want to see them returned to government and to this nation."

Speaking of Italian immigrants, Reagan said they "had incredible courage and faith. They had a dream."

"We know their sacrifices." he continued. "We know their hidden glory. Their spirit cannot be allowed to be forgotten. And as president of the United States I will make certain that the values that made them endure and work and build will be at the heart of all that is done in the White House and throughout government."